With only about a month left to go before the film’s planned June 29 release, Paramount has announced that the only big summer action movie on their slate—G.I. Joe: Retaliation, the sequel to 2009’s G.I. Joe movie—will be delayed for nine more months as a third dimension is added to the film. This comes after a heavy promotional push for the movie, including a Super Bowl ad, complicated websites and all the usual buzz-building stuff. The last-minute change was a shock to director Jon M. Chu, according to the Los Angeles Times, who on Monday said that he was ready for the release.

Retaliation stars Channing Tatum, reprising his role from 2009, but Tatum is injured early on and leaves a new group of soldiers to save the day. The new team is led by Dwayne Johnson and Bruce Willis, the latter of whom plays the Joe (even though the original G.I. Joe toys are a reference to the everyman soldier, the movie has an actual guy). Chu has plenty of schlocky 3D cred to his name—he did the Justin Bieber movie and Step Up3D—but the Hollywood Reportersays that at South by Southwest the director was open about the studio balking at the time and money needed to do 3D right, and how he was excited to shoot film (1.2 million feet of it, apparently) instead. Adding 3D in post production is nothing new, and the studio executives who made the financial decision to delay surely learned about sunk costs in Econ 101, but it’s not hard to imagine that they’re regretting not filming in 3D from the get-go.

There are lots of theories out there about why Paramount picked March over June. The original date was sandwiched between Brave and The Amazing Spider-Man. Overseas audiences crave 3D. All the promotion wasn’t leading to tangible excitement. This month’s Battleship left audiences with a bad taste in their mouths about toys-cum-movies. The movie already cost $125 million and the first one didn’t make much more than that; 3D ticket prices may help recoup the costs. The spring month is not so crowded and yet Hunger Games demonstrated that a major March opening is possible.

And allow us to put forward another, new, completely unfounded suggestion: the studio’s already on the hook for more than $100 million, but maybe they want to save a few pennies on the redesign of all the promotional materials. After all, the movie’s new release date is the next possible Friday the 29th on the calendar.